tree: https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git coresched head: 08584c8e5f653b2f341504289f843d576c83893e commit: 9c8cba1070926caa0850bc44d157109d819eb6d0 [18/24] entry/idle: Enter and exit kernel protection during idle entry and exit config: riscv-randconfig-r036-20210112 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 68ff52ffead2ba25cca442778ab19286000daad7) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install riscv cross compiling tool for clang build # apt-get install binutils-riscv64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git/commit/?i... git remote add jfern https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git git fetch --no-tags jfern coresched git checkout 9c8cba1070926caa0850bc44d157109d819eb6d0 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/riscv/include/asm/io.h:149: include/asm-generic/io.h:564:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] return inw(addr); ^~~~~~~~~ arch/riscv/include/asm/io.h:56:76: note: expanded from macro 'inw' #define inw(c) ({ u16 __v; __io_pbr(); __v = readw_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:88:76: note: expanded from macro 'readw_cpu' #define readw_cpu(c) ({ u16 __r = le16_to_cpu((__force __le16)__raw_readw(c)); __r; }) ^ include/uapi/linux/byteorder/little_endian.h:36:51: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) ((__force __u16)(__le16)(x)) ^ In file included from kernel/sched/idle.c:9: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/riscv/include/asm/io.h:149: include/asm-generic/io.h:572:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] return inl(addr); ^~~~~~~~~ arch/riscv/include/asm/io.h:57:76: note: expanded from macro 'inl' #define inl(c) ({ u32 __v; __io_pbr(); __v = readl_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:89:76: note: expanded from macro 'readl_cpu' #define readl_cpu(c) ({ u32 __r = le32_to_cpu((__force __le32)__raw_readl(c)); __r; }) ^ include/uapi/linux/byteorder/little_endian.h:34:51: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) ((__force __u32)(__le32)(x)) ^ In file included from kernel/sched/idle.c:9: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/riscv/include/asm/io.h:149: include/asm-generic/io.h:580:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] outb(value, addr); ^~~~~~~~~~~~~~~~~ arch/riscv/include/asm/io.h:59:68: note: expanded from macro 'outb' #define outb(v,c) ({ __io_pbw(); writeb_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:91:52: note: expanded from macro 'writeb_cpu' #define writeb_cpu(v, c) ((void)__raw_writeb((v), (c))) ^ In file included from kernel/sched/idle.c:9: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/riscv/include/asm/io.h:149: include/asm-generic/io.h:588:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] outw(value, addr); ^~~~~~~~~~~~~~~~~ arch/riscv/include/asm/io.h:60:68: note: expanded from macro 'outw' #define outw(v,c) ({ __io_pbw(); writew_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:92:76: note: expanded from macro 'writew_cpu' #define writew_cpu(v, c) ((void)__raw_writew((__force u16)cpu_to_le16(v), (c))) ^ In file included from kernel/sched/idle.c:9: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/riscv/include/asm/io.h:149: include/asm-generic/io.h:596:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] outl(value, addr); ^~~~~~~~~~~~~~~~~ arch/riscv/include/asm/io.h:61:68: note: expanded from macro 'outl' #define outl(v,c) ({ __io_pbw(); writel_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:93:76: note: expanded from macro 'writel_cpu' #define writel_cpu(v, c) ((void)__raw_writel((__force u32)cpu_to_le32(v), (c))) ^ In file included from kernel/sched/idle.c:9: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/riscv/include/asm/io.h:149: include/asm-generic/io.h:1005:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port; ~~~~~~~~~~ ^ In file included from kernel/sched/idle.c:9: kernel/sched/sched.h:1231:17: warning: declaration of 'struct sched_group' will not be visible outside of this function [-Wvisibility] struct sched_group *group) ^ In file included from kernel/sched/idle.c:11: #include <asm/entry-common.h> ^~~~~~~~~~~~~~~~~~~~ 8 warnings and 1 error generated. vim +10 include/linux/entry-common.h 142781e108b13b2b Thomas Gleixner 2020-07-22 9 142781e108b13b2b Thomas Gleixner 2020-07-22 @10 #include <asm/entry-common.h> 142781e108b13b2b Thomas Gleixner 2020-07-22 11 :::::: The code at line 10 was first introduced by commit :::::: 142781e108b13b2b0e8f035cfb5bfbbc8f14d887 entry: Provide generic syscall entry functionality :::::: TO: Thomas Gleixner <tglx(a)linutronix.de&gt; :::::: CC: Thomas Gleixner <tglx(a)linutronix.de&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org